Hadith 2:428

Narrated 'Uqba bin 'Amir:

One day the Prophet went out and offered the funeral prayers of the
martyrs of Uhud and then went up the pulpit and said, "I will pave the
way for you as your predecessor and will be a witness on you. By
Allah! I see my Fount (Kauthar) just now and I have been given the
keys of all the treasures of the earth (or the keys of the earth). By
Allah! I am not afraid that you will worship others along with Allah
after my death, but I am afraid that you will fight with one another
for the worldly things."